Agro-radioecological and phytochemical characteristics ofEleutherococcus senticosus under different cultivation methodsand environmental conditions of Armenia

Abstract

Background: Eleutherococcus senticosus (ES) (Rupr. and Maxim.) is a perennial medicinal plant widely used in traditional Eastern medicine. It is valued for its adaptogenic, immunomodulatory, and antioxidant properties, attributed to its rich content of bioactive secondary metabolites, including phenols and flavonoids. Due to increasing global demand for plant-based therapeutics and dietary supplements, the cultivation of ES has garnered significant interest. ES has traditionally been grown in forested or agricultural soils, primarily in East Asia and parts of Russia. However, nontraditional methods such as hydroponics are now being explored as sustainable alternatives for producing high-quality medicinal raw materials under controlled conditions. Assessing the phytochemical composition and environmental safety- particularly the accumulation of heavy metals (HM) and radionuclides (RN) is important to ensuring the quality and safety of raw materials used for functional foods and medicines, and must meet the norms established by the WHO.

Objective: To evaluate the impact of traditional and hydroponic cultivation methods and different environmental conditions on the content of flavonoids, phenolic acids, HM (As, Cd, Pb, Cu, Zn, Sn), and gross β-radioactivity in the plant raw materials of ES.

Methods: The experiments were conducted in two radioecological zones of Armenia: in the Institute of Hydroponics Problems (IHP) in Ararat Valley and the Dilijan Forest Experimental Station (DFES), located 30 km and 90 km from the Armenian Nuclear Power Plant (ANPP), respectively. Phenolic compounds were analyzed using High-Performance Liquid Chromatography (HPLC), gross β-radioactivity was measured with a UMF-1500 radiometer, and HM concentrations were determined by inductively coupled plasma mass spectrometry.

Results: ES grown in Ararat Valley (hydroponically and in soil) had 1.8 and 2.7 times higher chlorogenic acid and rutin content, respectively, compared to DFES soil-grown plants. However, the level of ferulic acid was lower in hydroponic plants - 1.1 times and in soil-grown (IHP) plants - 1.3 times, compared to DFES. Quercetin content remained relatively unchanged regardless of cultivation methods and agroecological conditions. Among the HM we have studied, the most toxic from a health perspective are Pb, As, and Cd. However, Cu and Zn are essential bio metals and are incorporated into the hydroponic nutrient solution recommended by Davtyan. The content of HM in plants grown hydroponically was arranged in the following descending order: Zn>Cu>Pb>Sn>As>Cd; in plants grown in IHP soil: Cu>Zn>Pb>As>Sn>Cd, and in plants grown in DFES soil: Cu>Pb>Zn>As>Sn>Cd. HM levels in IHP soil-grown plants were 1.7 times higher than those in DFES, while hydroponic cultivation reduced HM accumulation by 1.1 times. Zn content in hydroponic plants was 1.7 times higher than in IHP soil-grown plants and 7.2 times higher than in DFES soil-grown plants. HM concentrations meet the WHO norm. The various parts of the ES form the following descending order according to the level of the gross β-radioactivity: fruit > leaf > stem > root, with all values below the WHO safety threshold (< 1.0 Bq g-1), confirming radioecological safety of the obtained plant raw material. 

Novelty: For the first time in Armenia, the accumulation of HM in ES plant raw material grown in hydroponic and soil conditions in various radioecological zones was investigated.

Conclusion: Regardless of cultivation method or environmental conditions, ES leaves meet WHO safety standards for HM content and gross β-radioactivity, confirming their suitability as an ingredient in functional foods and dietary supplements.

Keywords: hydroponics, soil, chlorogenic acid, ferulic acid, rutin, heavy metals, gross β-radioactivity, radioecological safety.